Rotary fluid pressure device



Sept. 6, 1966 L. CHARLSON ROTARY FLUID PRESSURE DEVICE 2 Sheets-Sheet .L

Filed Jan. 22, 1965 34 a. fuzzy P 6, 1966 1.. 1.. CHARLSON 3,270,682

ROTARY FLUID PRESSURE DEVICE Filed Jan. 22, 1965 2 Sheets-Sheet 3 1x; vm "1 m Lwwv L CHAELS'ON .47 T OEIVE V United States Patent 3,270,682 ROTARY FLUID PRESSURE DEVICE Lynn L. Charlson, Minneapolis, Minn., assignor to Germane Corporation, Minneapolis, Minn., a corporation of Minnesota Filed Jan. 22, 1965, Ser. No. 427,379 6 Claims. (Cl. 103--130) This invention relates to rotary fluid pressure motors and pumps of the kind which utilize the type of gear mechanism disclosed in United States Patent No. 1,682,- 563, issued August 28, 1928, to Myron P. Hill.

The mechanism disclosed in the Hill patent is referred to in the art as a gerotor and consists of an internally toother ring member and an externally toothed star memher which partakes of a hypocycloida] movement and travels in an orbit about the axis of the ring member.

An object of. the present invention is to provide a rotary fluid pressure motor or pump of the gerotor type having a new and improved valving and drive system.

Other objects and advantages will become apparent from the following specification, appended claims and attached drawings.

In the drawings:

FIG. 1 is a longitudinal sectional view of a rotary fluid pump or motor embodying the invention and taken on line II of FIG. 2;

FIG. 2 is an end view from the left side of FIG. 1;

FIG. 3 is a transverse sectional view taken on line III-III of FIG. 1;

FIG. 4 is a transverse sectional view taken on line IV-lV of FIG. 1; and

HG. 5 is a sectional view taken on line V-V of FIG 4.

In the illustrated embodiment of the invention there is provided a casing comprising generally cylindrically shaped sections 2, 4, 6, 8 and 10. These casing sections are held together in axial alignment by a plurality of circumferentially spaced bolts 12.

Casing sections 6, see FIGS. 1, 3, 4 and 5, is generally annular in shape and in the illustrated embodiment of the invention casing section 6 is the ring member of the gerotor mechanism. Casing or ring member 6 has internal teeth 13 and forms the outer wall of a chamber. An externally toothed star member 14, having at least one fewer teeth 16 than ring member 6, is disposed eccentrically in the chamber or space formed and surrounded by ring member 6. Star member is moveablc orbitally relative to the ring member 6, the axis 18 of star member 14 being moveahlc in an orbital path about the axis 20 of ring member 6. During orbital movement of star member 14 the teeth 16 thereof intermesh with the ring member teeth 13 in sealing engagement to form expanding and contracting cells 22 which are equal in number to the number of star member teeth 16. Casing sections 4 and 8 are generally annularly shaped plates which form lateral walls for the cells 22.

With reference to FlGS. 3 and 4, the vertical plane or centerline 24 incidentally represents the line of eccentricity for the star member 14 for that particular position of the star member relative to the ring member 6. The line of eccentricity 24 is defined as a line which passes through the axes 18 and 20 of the star and ring members 14 and 6. During orbital movement of the star 14, and assuming the orbital movement is clockwise viewed in FIG. 3, the cells 22 on the left side of the line of eccentrcity would be expanding and the cells 22 on the right side would be contracting. If the device is used as a motor, fluid under pressure is directed to the expanding cells and exhausted from the contracting cells. If the device is used as a pump, fluid is sucked into the expanding cells and delivered under pressure from the Patented Sept. 6, 1966 ice contracting cells. The valving arrangement which facilitates the pumping or motor action will be described further on herein.

Star member 14 has a bore 26 concentric with the axis 18 thereof. A spool member 28 is rotatably disposed in the bore 26 and the axial length of spool 28 is less than the axial length of bore 26. Spool 28 is retained in the illustrated position in bore 26 by being disposed between plate 4 and a pin 30 which is attached to the star 14 by being press fitted in holes 31 thereof and which extends diametrically across the bore 26 thereof.

Spool 28 has a central fluid tight partition 32. A plurality of circumfcrenlially arranged ports are provided in spool 28 comprising a first series of ports 34 on the one side of partition 32 and a second series of ports 36 on the other side of partition 32. The second series of ports 36 are arranged so as to alternate circumferentially relative to the first series of ports 34 and it will be observed by comparing FlGS. 3 and 4 that the series of ports are circumferentially offset relative to the series of ports 36.

A series of passages 38 are provided in star member 14, each of which passages extends radially from the star bore 26 to a point between two star teeth 16. Each of the passages 38 is illustrated as being axially elongated and so positioned relative to spool 28 so as to communicate with each of the series of ports 34 and 36 when there is relative rotational movement between star member 14 and spool 28. If desired, each of the passages 38 may be divided into two axially aligned passages which would be in planes that register axially with the series of ports 34 and 36 in spool 28.

Casing section 2 has a cylindrical bore 39 at one end thereof and a cylindrical counterbore 40 adjacent to bore 39. Casing section 10 has a cylindrical bore 42 and both countcrbore 40 and bore 42 are concentric relative to the axis 20 of ring member 6. Casing section 2 has a radially extending bore 44 which intersects and has lluid communication with counterbore 40. Casing section 10 has a radially extending bore 46 which intersects and has fluid communication with bore 42. For convenience bore 44 will be referred to an an inlet bore and bore 46 will be referred to an an outlet bore. It will be understood, ho wcver, that bore 46 may also serve as an inlet and bore 44 may serve as an outlet.

Casing section 2 has a cylindrically shaped anchor member 48 rotatably disposed in the counterbore 40 there-- of. One end of anchor 48 has a reduced diameter to form an annular shoulder 49 which bears against the annular shoulder formed between bore 39 and countcrhorc 40 to restrain anchor 48 from moving outwardly to the left. Anchor 48 has a bore 50 and a pin 52 is attached to anchor 48 by being press fitted in holes 53 thereof and extends diametrically across bore 50.

Spool 28 has bores 54 and 56 on opposite sides of the spool partition 32. Brackets 57 are provided which cxtcnd axially from partition 32 and a pin 58 is attached to spool 28 through brackets 57 and extends diametrically across bore 54. A universal joint shaft 60 extends between anchor 48 and spool 28. One end 62 of shaft 60 is disposed in anchor bore 50 and has a frustosphcrical shape of the same diameter as anchor bore 50. The end 62 of shaft 60 is bifurcated to form a slot 64 having the same width as the diameter of pin 52 which is accommodatcd by the slot 64. The other end of shaft 60 is bifurcated to form a slot 68 having the same width as the diameter of spool pin 58 which is accommodated by the slot 68.

The assembly which comprises the anchor 48 and shaft 60, which may be referred to as spool anchoring means, is retained in its axial position in the casing bore 40 by reason of being disposed between the casing shoulder 49 and the spool pin 58.

The angular position of pin 52 determines the angular relationship between spool 28 and star 14 which in turn determines the direction of rotation of star 14 relative to ring member 6. Anchor 48 is made angularly adjustable about its own axis relative to easing section 2 so that the angular relationship between spool 28 and star 14 can be varied. For this purpose there is provided an adjusting ring 68 which is fixedly attached to anchor 48 with a bolt 69 and a dowel pin 70. The angular position of anchor 48 and adjusting ring 68 relative to casing section 2 is made adjustable by providing an arcuate slot 72 in adjusting ring 68 and a bolt 74 which extends through slot 72 into a threaded hole 76 in casing section 2. The manner in which the angular adjustment of anchor 48 is effective to determine the direction of gyration and rotation of star 14 will be described further on herein.

Bore 42 of easing section has a stepped shaft 80 rotatably disposed therein. Shaft 80 is axially retained in bore 42 by being disposed between annular plate 8 and a snap ring 82. Shaft 80 has an axially extending bore 84 concentric with the ring member axis 20. A pin 86 is attached to shaft 80 by being press fitted in holes 85 and pin 86 extends diametrically across bore 84. A universal joint shaft 88 extends between shaft 80 and star member 14. One end 90 of shaft 88 is disposed in shaft bore 84 and has a frustospherical shape of the same diameter as shaft bore 84. Shaft end 90 is bifurcated to form a slot 92 having the same width as the diameter of pin 86 which is accommodated by the slot 92. The other end of shaft 88 is bifurcated to form a slot 96 having the same width as the diameter of star pin which is accommodated by the slot 96.

Shaft 80 has a circumferential groove 97 which registers axially with port 46 and a plurality of radial openings 98 which communicate with the shaft bore 84 and circumferential groove 97 to provide fluid communication between casing port 46 and spool bore 56.

Star member 14 is eccentrically disposed relative to ring member 6. as mentioned above, and shaft 88 is thus always in a cocked or tilted position relative to shaft 80, which has the same axis 20 as ring member 6, and relative to the axis 18 of star member 14. In operation a star member 14 having six teeth 16 will make one revolution about its own axis 18 for every six times the star member orbits in the opposite direction about the axis 20 of the ring member 6. Thus, the left end of shaft 88 has both orbital and rotational movement in common with the star member 14 while the right end of shaft 88 has only rotational movement in common with shaft 80. The connections between shaft 88 and shaft 80 and between shaft 88 and star member 14 are forms of universal joints which permit shaft 88 to have the motion described above. When the device is utilized as a pump, star member 14 will be gyrated by a turning force applied to shaft 80 and transmitted to star member 14 through shaft 88. When the device is used as a motor, the force created by the rotation of star member 14 about its own axis 18 will be transmitted through shaft 88 to shaft 80 to cause turning of shaft 80.

Assuming that the fluid pressure device is functioning as a motor, pressurized fluid is introduced through one of the ports such as port 44 into casing bore and spool bore 54, through certain passages 34 in spool valve 28 which as viewed in FIG. 3 are on the right side of the line of eccentricity 24, through certain passages 38 in the star 14 which as viewed in FIGS. 3 and 4 are on the right side of the line of eccentricity 24, to certain gerotor cells 22 which as viewed in FIGS. 3 and 4 are on the right side of the line of eccentricity 24.

The pressurized fluid directed to the cells on the right side of the line of eccentricity 24 causes star 14 to orbit in a counterclockwise di ection and cause collapsing of the cells 22 on the left side of the line of eccentricity 24. Fluid from the collapsing cells 22 flows through certain passages 38 in the star 14 which as viewed in FIGS. 3 and 4 are on the left side of the line of. eccentricity 24, through certain passages 36 in spool valve 28 which as viewed in FIG. 4 are on the left side of the line of eccentricity 24, to the spool bore 56 and the shaft bore 84, and through shaft ports 98 and circumferential groove 97 and out of the port 46.

The above description of fluid flow is only for an instantaneous condition in that the line of eccentricity 24 rotates about the axis 28 of ring member 6. As long as pressurized fluid is admitted through port 44, however, the pressurized fluid will always be admitted to cells 22 on the same side of the line of eccentricity 24 and fluid will always be exhausted on the other side of said line.

In operation, star 14 orbits relative to ring member 6 and spool 28 follows this orbital movement by reason of the universal joint characteristics of shaft 60. These universal joint characteristics of shaft are also effective to prevent rotation of spool 28 relation to ring memher 6 when the anchor member 48 is held in a fixed angular posiiton relative to casing section 2 and ring member 6. Star 14 rotates relative to ring member 6 in the opposite direction from which it orbits relative to ring member 6 and also rotates relative to spool 28. This rotation of start 14 causes each passage 38 thereof to register alternately with passages 34 and 36 of spool 28.

In the illustrated embodiment of the invention there are six passages 38 in the star 14 and seven each of the ports 34 and 36 in the spool 28. Assuming that pressurized fluid is introduced from port 44 to spool bore 54, it will be noted from FIG. 3 that only spool ports 34 and start passages 38 on the right side of the line of eccentricity 24 are in register and thus the pressurized fluid can only be admitted to the cells 22 on the right side of the line of eccentricity 24. On the left side of the line of eccentricity 24 (FIG. 3) there are no spool ports 34 which register with star passages 38. With regard to exhausting fluid from the cells 22 on the left side of the line of eccentricity 24, it will be noted from FIG. 4 that at the same instant only spool ports 36 of star passages 38 on said left side of the line of eccentricity 24 are in register and thus fluid is exhausted to spool bore 56 only from the cells 22 on the left side of the line of eccentricity 24. On the right side of the line of eccentricity 24 (FIG. 4) there are no spool ports 36 which registers with start passages 38.

The described characteristics relating to the registering of ports in supplying fluid to and exhausting fluid from the cells 22 are present for any position of the star 14 relative to the ring member 6 as long as the anchor 48 is maintained or held in the position indicated in the drawings. The orbiting direction of star 14 may be reversed by loosening bolt 74 and rotating anchor 48 a predetermined number of degrees clockwise or counterclockwise to a new position and again tightening bolt 74. If anchor 48 is rotated so that, with regard to FIG. 3, three spool ports 34 register with three star passages 38 on the left side of the line of eccentricity 24, pressure will be supplied to the left side and star 14 will then be gyratable in a clockwise direction. With regard to FIG. 4, this adjustment of anchor 48 will automatically cause three spool ports 36 to register with three star passages 38 on the right side of the line of eccentricity 24 to provide for the exhausting of the cells 22 on the right side of the line of eccentricity 24.

The number of degrees anchor 48 must be turned or rotated to effect a reversal of the orbiting direction of star 14 is dependent upon the ratio between the number of teeth in the star and ring members. For a 6 to 7 ratio as in the illustrated embodiment the anchor 48 would have to be rotated of a turn in either direction. Other examples would be of a turn for a 5 to 6 ratio and of a turn for a 7 to 8 ratio.

Referring to the operation of the fluid pressure device generally, the providing of one less passages 38 in the star 14 than the number of fluid supply ports 34 or fluid exhaust ports 36 in the spool 28 produces a commutating action whereby supply ports 34 only register with star passages 38 on one side of the line of eccentricity 24 and exhaust ports 36 only register with star passages 38 on the other side of the line of eccentricity. In the illustrated embodiment of the invention the star 14 orbits six times relative to ring member 6 for every time it rotates relative to ring member 6. During rotation of the star 14 about spool 28, one-sixth of a rotation of star 14 in a clockwise direction will cause pressurized fluid from the spool ports 34 to be admitted to all of the six star passages 38 one after the other in sequence in a counterclockwise direction and the line of eccentricity 24 will make one complete revolution in a counterclockwise direction. Likewise during said one-sixth of a rotation, fluid will be exhausted from all of the six star passages 38 one after the other in sequence in a counterclockwise direction by the spool ports 36.

Shaft 80 is provided so that the device can be operated as a pump or a motor but may be omitted entirely in an installation Where the invention is utilized for a meter or the like which does not require the equivalent of shaft 80. In the illustrated embodiment of the invention the universal joint shaft 88 which connects shaft 80 to star 14 is effective to cause shaft 80 to rotate at the same speed that star 14 rotates relative to ring member 6. As an alternative, shaft 88 could be omitted and an eccentric connection could be provided between shaft 80 and star bore 26 which would cause shaft 80 to rotate at the same speed that star 14 orbits relative to the ring member 6.

From the foregoing it will be understood that the rotary fluid pressure device described may be used as a pump, motor or metering device. It may be utilized as a pump by connecting one of the ports 44 or 46 to a source of fluid and rotating the shaft 80 in the correct direction or as a motor by connecting one of the ports 44 or 46 to a source of fluid pressure and connecting shaft 80 to a mechanical device desired to be driven. When used as a pump a relatively slow speed imparted to shaft 80 will cause relatively rapid orbiting of star member 14 and result in a high fluid delivery rate. When used as a motor the shaft 80 makes one rotation for every six orbiting cycles of the star 14, in a case where star 14 has six teeth, and as a result the shaft 80 produces a relatively high torque at a relatively slow speed.

While one embodiment of the invention is described here, it will be understood that it is capable of modification, and that such modification, including a reversal of ports, may be made Without departure from the spirit and scope of the invention as defined in the claims.

What I claim is:

1. In a fluid pressure device, a casing, fluid inlet and outlet means, an internally toothed ring member defining the outer wall of a chamber, a cooperating externally toothed star member having fewer teeth than said ring member disposed eccentrically in said chamber and being capable of orbital movement about the axis of said ring member, the teeth of said members intermeshing in sealing engagement to form expanding cells on one side of the line of eccentricity and contracting cells on the other side of said line during relative movement between said members, said star member having a concentric bore and being rotatable about its own axis in the opposite direction and at a slower speed than said orbital movement during relative rotation between said members, a spool member rotatably disposed in said star member bore, spool anchoring means for allowing said spool to follow said orbital movement of said star member but preventing rotational movement of said spool relative to said ring member during operation of said device, a plurality of circumferentially arranged ports in said spool member comprising a first series of circumferentially arranged fluid feeding ports communicating with said fluid inlet means and a second series of ports being arranged alternately relative to said first series of ports a fluid tight partition in said spool member separating said first series of ports from said second series of ports, a series of passages in said star member which extend from spaces between the teeth thereof to said bore thereof, said series of star passages upon relative movement between said star and spool members being sequentially communicable with each of said plurality of spool ports to effect communication between said inlet means and the expanding cells on one side of said line of eccentricity and between said outlet means and said contracting cells on the other side of said line of eccentricity.

2. A fluid pressure device according to claim 1 including shaft means journalled in said casing and operatively connected to said star member for rotational movement responsive to movement of said star member relative to said ring member.

3. A fluid pressure device according to claim 2 including a universal joint connection between said star member and said shaft means, said universal joint connection having one end thereof attached to said star member for common orbital and rotational movement therewith and the other end thereof attached to said shaft means for common rotational movement therewith.

4. A fluid pressure device according to claim 3 wherein said universal joint connection includes pins in said star member and said shaft means with said pins being at right angles to each other.

5. A fluid pressure device according to claim 1 wherein said spool anchoring means includes a universal joint connection between said spool and said casing.

6. A fluid pressure device according to claim 5 wherein said anchoring means includes an angularly adjustable anchor journalled in said casing, said anchor being adjustable to angularly adjust said star member relative to said ring member to cause rotation of said star member in either direction relative to said ring member.

References Cited by the Examiner UNITED STATES PATENTS Re. 25,126 2/1962 Charlson 9156 Re. 25,291 12/1962 Charlson 91-56 1,682,563 8/1928 Hill 230-141 2,758,573 8/1956 Krozal 9156 2,866,417 12/1958 Nubling 123-8 2,989,951 6/1961 Charlson l2312 3,087,436 4/1963 Dettlof et al 103130 3,175,503 3/1965 Molly 103130 FOREIGN PATENTS 1,133,762 11/1956 France.

9,359 1915 Great Britain.

MARK NEWMAN, Primary Examiner.

W. J. GOODLIN, Assistant Examiner. 

1. IN A FLUID PRESSURE DEVICE, A CASING, FLUID INLET AND OUTLET MEANS, AN INTERNALLY TOOTHED RING MEMBER DEFINING THE OUTER WALL OF A CHAMBER, A COOPERATING EXTERNALLY TOOTHED STAR MEMBER HAVING FEWER TEETH THAN SAID RING MEMBER DISPOSED ECCENTRICALLY IN SAID CHAMBER AND BEING CAPABLE OF ORBITAL MOVEMENT ABOUT THE AXIS OF SAID RING MEMBER, THE TEETH OF SAID MEMBERS INTERMESHING IN SEALING ENGAGEMENT TO FORM EXPANDING CELLS ON ONE SIDE OF THE LINE OF ECCENTRICITY AND CONTACTING CELLS ON THE OTHER SIDE OF SAID LINE DURING RELATIVE MOVEMENT BETWEEN SAID MEMBERS, SAID STAR MEMBER HAVING A CONCENTRIC BORE AND BEING ROTATABLE ABOUT ITS OWN AXIS IN THE OPPOSITE DIRECTION AND AT A SLOWER SPEED THAN SAID ORBITAL MOVEMENT DURING RELATIVE ROTATION BETWEEN SAID MEMBERS, A SPOOL MEMBER ROTATABLY DISPOSED IN SAID STAR MEMBER BORE, SPOOL ANCHORING MEANS FOR ALLOWING SAID SPOOL TO FOLLOW SAID ORBITAL MOVEMENT OF SAID STAR MEMBER BUT PREVENTING ROTATIONAL MOVEMENT OF SAID SPOOL RELATIVE TO SAID RING MEMBER DURING OPERATION OF SAID DEVICE, A PLURALITY OF CIRCUMFERENTIALLY ARRANGED PORTS IN SAID SPOOL MEMBER COMPRISING A FIRST SERIES OF CIRCUMFERENTIALLY ARRANGED FLUID FEEDING PORTS COMMUNICATING WITH SAID FLUID INLET MEANS AND A SECOND SERIES OF PORTS BEING ARRANGED ALTERNATELY RELATIVE TO SAID FIRST SERIES OF PORTS A FLUID TIGHT PARTITION IN SAID SPOOL MEMBER SEPARATING SAID FIRST SERIES OF PORTS FROM SAID SECOND SERIES OF PORTS, A SERIES OF PASSAGES IN SAID STAR MEMBER WHICH EXTEND FROM SPACES BETWEEN THE TEETH THEREOF TO SAID BORE THEREOF, SAID SERIES OF STAR PASSAGES UPON RELATIVE MOVEMENT BETWEEN SAID STAR AND SPOOL MEMBERS BEING SEQUENTIALLY COMMUNICABLE WITH EACH OF SAID PLURALITY OF SPOOL PORTS TO EFFECT COMMUNICATION BETWEEN SAID INLET MEANS AND THE EXPANDING CELLS ON ONE SIDE OF SAID LINE OF ECCENTRICITY AND BETWEEN SAID OUTLET MEANS AND SAID CONTRACTING CELLS ON THE OTHER SIDE OF SAID LINE OF ECCENTRICITY. 